1. Field of the Invention
The present invention relates to a stacked coil element and a method for manufacturing the same.
2. Description of the Related Art
A stacked coil element can be obtained, for example, by stacking and integrating insulator sheets having, on main surfaces thereof, conductor patterns shaped to form a portion of a coil.
The insulator sheet having, on the main surface thereof, the conductor pattern shaped to form a portion of the coil can be obtained, for example, by etching a conductive foil of an insulator sheet having the conductive foil affixed to an entire main surface thereof. Alternatively, instead of using the insulator sheet having the conductive foil affixed preliminarily to the entire surface thereof, the insulator sheet can be obtained by screen printing a conductive paste onto a main surface of an insulator sheet to which a conductive foil is not affixed.
Japanese Patent Laying-Open No. 2007-281025 describes a configuration of a stacked chip coil in which a through hole penetrating through a first magnetic material portion is formed and a second magnetic material portion is arranged in this through hole in order to achieve a high inductance value as well as an excellent DC superimposition property and a low resistance.
It has been known that in a stacked coil element, a conductor pattern forming a portion of a coil is obtained by etching or screen printing. In either case, however, an end of the obtained conductor pattern has a surface that is not perpendicular to, but inclined with respect to a main surface, and a base portion of the inclined surface is thin for use as the conductor pattern. In the case where the end of the conductor pattern has such a thin portion on the inner peripheral side of the coil, an electric current concentrates on this thin portion of the end on the inner peripheral side when the electric current is actually passed through the stacked coil element, which causes electrical energy loss.